How to fix this error in interpolation?

Hi,

I have a set of data to be interpolated for two files. I could use the code below when the second file (representing Y axis) has 11 columns.

However, when the second file (representing Y axis) has only two columns, it shows the following error:

Error using griddedInterpolant

The grid vectors must contain unique points.

Error in interp1 (line 151)

F = griddedInterpolant(X,V,method);

Error in File11 (line 18)

x2 (k,:) = interp1(y3, x3, A(:,i), 'linear');

clear; clc;
Folder = cd;
N=1;
x2    = zeros(N, 10);
for k = 1:N;
  Driftt  = sprintf('Drift%d.out', k);
  Reactt  = sprintf('React%d.out', k);
  matDrift     = importdata(fullfile(Folder, Driftt));
  matReact = importdata(fullfile(Folder, Reactt));
  x1= matDrift(:,2);
  y1= -matReact(:,2);
[x3, ix] = unique(x1);
y3       = y1(ix);

A=dlmread('result_all.txt');

for i=1:size(A,2)
    x2 (k,:) = interp1(y3, x3, A(:,i), 'linear');
    temp=x2(k,:);
temp(isnan(temp))=0.05;
x2(k,:)=temp;

    fid=fopen(['result_' num2str(i) '.txt'],'a');
    fprintf(fid,'%f\n',x2(k,:)); 
    fclose(fid);
end
end

[Ismail Qeshta]

I have just tried to use "unique" with y3, but I got the following error:

Error using interp1>reshapeAndSortXandV (line 424)

X and V must be of the same length.

Error in interp1 (line 93)

[X,V,orig_size_v] = reshapeAndSortXandV(varargin{1},varargin{2});

Error in File11 (line 19)

x2 (k,:) = interp1(y3, x3, A(:,i), 'linear');

Answer 1

[Matt J]

interp1 is complaining that y3 has repeated elements. They are required to be unique and monotonic.

[Ismail Qeshta]

Hi Matt,

Many thanks for your reply. Aren't they unique?

[Matt J]

Nope.

K>> numel(y3)

ans =

   267

K>> numel(unique(y3))

ans =

   266

[Ismail Qeshta]

Thanks Matt.

Would it be possible to ask how to incorporate this into my code?